1. Field of the Invention
The present invention relates to a DVD disc, a device and a method for reproducing the same and more particularly, to an audio private DVD disc, a device and a method for reproducing the same.
2. Description of the Related Art
A digital versatile disc (hereinafter, referred to as DVD)-video disc is divided into a video data area, a sub-picture data area, a navigation data area, and an audio data area, and the whole capacity thereof is 4.7/8.5 Gbyte and the transmission speed is 10.08 Mbps. DVD specification allows a maximum 9 Mbps for a video stream, a maximum of 6 Mbps for an audio stream and a maximum of 6 Mbps for a sub-picture stream. However, the sum of all these streams should not exceed 10.08 Mbps, the maximum transmission speed of the entire DVD system. The data compressed with an MPEG-1/MPEG-2 video system is stored at the video area of the DVD-video disc and at maximum, eight audio data streams are stored in the audio data area thereof using linear PCM (pulse code modulation), AC-3, MPEG-2, DTS, and SDDS systems. A device for reproducing the DVD-video disc decodes the video data recorded on the DVD-video disc, restores the decoded data as the moving picture, converts the restored moving picture into analog screen information, and outputs the converted information. Also, the aforesaid device decodes the audio data and converts the decoded audio data into an analog audio signal, thereby outputting the converted signal.
The audio data recorded at the DVD-video disc as described above can provide the best sound quality in case of using the linear PCM system. However, in case of using the linear PCM system, two channels can be serviced in the audio data which is quantized at the sampling frequency of 96 KHz by 24 bits, eight channels can be serviced in the audio data which is quantized at the sampling frequency of 48 KHz by 16 bits, and channels or sampling frequencies exceeding the number of the above channels and the sampling frequencies can not be used. That is, since the DVD-video disc and the device for reproducing the same should process the video data at the maximum of 9 Mbps and the audio data at the maximum of 6 Mbps at the same time, there is a problem in that it is difficult to provide a high sound quality with multi-channels.
Coping with the foregoing problems, there have been suggested methods for improving the audio quality by using a system which is not used in the DVD-video disc. However, the methods cannot be reciprocally used with the DVD-video disc, so that the information efficiency may be lowered, thereby having a difficulty in providing the audio data of the multi-channels.
An object of the present invention is to provide a disc for recording audio data of multi-channels which may be used reciprocally in a device for reproducing data from a DVD-video disc.
Another object of the present invention is to provide a DVD-audio disc which extends and stores the audio data at an area where non-audio data is normally stored, such as in a video area and a sub-picture area in the DVD video disc.
Still another object of the present invention is to provide a device for reproducing audio data in the DVD audio disc included with an audio data area, a video data area, a sub-picture area, other data areas, the areas other than the audio data area storing extended audio data.
Yet another object of the present invention is to provide a method for reproducing audio data in the DVD-audio disc included with an audio data area, a video area, a sub-picture area, and other data areas for storing extended audio data.
In order to accomplish the objects of the present invention, there is provided a DVD audio disc, including a DVD video area including a video management information area and a plurality of video title set areas; the video title set area including areas for storing video title set information, a video object set menu, and a plurality of video object set titles; the video title set information area including the video tide set information management table; the video title set information management table area including a video title set video attribute having a video compression mode area for indicating an MPEG video compression mode and an extended audio data mode, a video title set sub-picture attribute having a sub-picture coding mode area for indicating a sub-picture mode and the extended audio data mode, and a video title set audio attribute including an audio coding mode area; video object sets of the video title set title including a plurality of video packs, sub-picture packs and audio packs, the packs having a plurality of frames in which a header and real data are recorded; the video stream and sub-picture stream including an extended audio header having a channel number, a sampling frequency, and a plurality of the channel headers corresponding to the channel number; the channel headers including an area for storing the channel number of the corresponding channel, a coding mode of the extended audio data, usage of the extended audio data, a quantization bit number of the extended audio data, and a sampling frequency of the extended audio data; and the usage area of the extended audio data indicative of corresponding extension usage such as bit extension, bandwidth extension, and channel extension, whereby the video stream and the sub-picture stream of the DVD area can be reproduced.
Further, the present invention is provided with a device for reproducing a DVD audio disc, comprising a basic audio decoder; an extended audio decoder; and an extender, whereby the basic audio decoder reproduces data of an audio pack, the extended audio decoder reproduces the extended audio data and the extender combines the extended audio data with basic audio data, thereby performing bit extension, bandwidth extension, and channel extension of the audio data and outputs the combined audio data.
Furthermore, the present invention provides a method for reproducing data from a DVD audio disc, including the steps of analyzing video and sub-picture attributes of the video title set to be reproduced; enabling a basic audio decoder and an extended audio decoder in an extended audio mode; checking usage of the extended audio data included in channel headers of the corresponding video title set; and combining the extended audio data decoded at the extended audio decoder, at the basic audio decoder to be output.